GB1571924A - Carbon aggregates - Google Patents

Carbon aggregates Download PDF

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Publication number
GB1571924A
GB1571924A GB921577A GB921577A GB1571924A GB 1571924 A GB1571924 A GB 1571924A GB 921577 A GB921577 A GB 921577A GB 921577 A GB921577 A GB 921577A GB 1571924 A GB1571924 A GB 1571924A
Authority
GB
United Kingdom
Prior art keywords
carbon
solvent
adhesive
particles
mixture
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
GB921577A
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
BONDED CARBON FILTERS Ltd
Original Assignee
BONDED CARBON FILTERS Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by BONDED CARBON FILTERS Ltd filed Critical BONDED CARBON FILTERS Ltd
Priority to GB921577A priority Critical patent/GB1571924A/en
Publication of GB1571924A publication Critical patent/GB1571924A/en
Expired legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D39/00—Filtering material for liquid or gaseous fluids
    • B01D39/14—Other self-supporting filtering material ; Other filtering material
    • B01D39/20—Other self-supporting filtering material ; Other filtering material of inorganic material, e.g. asbestos paper, metallic filtering material of non-woven wires
    • B01D39/2055—Carbonaceous material
    • B01D39/2058—Carbonaceous material the material being particulate
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D39/00—Filtering material for liquid or gaseous fluids
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D39/00—Filtering material for liquid or gaseous fluids
    • B01D39/14—Other self-supporting filtering material ; Other filtering material
    • B01D39/16—Other self-supporting filtering material ; Other filtering material of organic material, e.g. synthetic fibres
    • B01D39/1638—Other self-supporting filtering material ; Other filtering material of organic material, e.g. synthetic fibres the material being particulate
    • B01D39/1646—Other self-supporting filtering material ; Other filtering material of organic material, e.g. synthetic fibres the material being particulate of natural origin, e.g. cork or peat
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
    • B01J20/02—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material
    • B01J20/20—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising free carbon; comprising carbon obtained by carbonising processes
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/28—Treatment of water, waste water, or sewage by sorption
    • C02F1/283—Treatment of water, waste water, or sewage by sorption using coal, charred products, or inorganic mixtures containing them
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2239/00—Aspects relating to filtering material for liquid or gaseous fluids
    • B01D2239/04—Additives and treatments of the filtering material
    • B01D2239/0471—Surface coating material
    • B01D2239/0485—Surface coating material on particles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2239/00—Aspects relating to filtering material for liquid or gaseous fluids
    • B01D2239/08—Special characteristics of binders
    • B01D2239/086—Binders between particles or fibres
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2239/00—Aspects relating to filtering material for liquid or gaseous fluids
    • B01D2239/12—Special parameters characterising the filtering material
    • B01D2239/1241—Particle diameter

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Organic Chemistry (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Geology (AREA)
  • Analytical Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Hydrology & Water Resources (AREA)
  • Engineering & Computer Science (AREA)
  • Environmental & Geological Engineering (AREA)
  • Water Supply & Treatment (AREA)
  • Filtering Materials (AREA)
  • Solid-Sorbent Or Filter-Aiding Compositions (AREA)

Description

(54) CARBON AGGREGATES (71) We, BONDED CARBON ALTERS LTD., a Company registered under the laws of Great Britain, of 158-164 Ravenscroft Road, Beckenham, Kent, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention concerns the production of an aggregate comprising particles of carbon.
Mouldings of any shape can be made to suit the particular application.
The use of activated carbon for purifying air and liquids is well known, but it is common to find that attempts to confine loose particles in a filter element are ineffective, allowing carbon to enter the air or liquids.
Existing methods of producing aggregates of carbon particles all suffer from disadvantages, either in performance or production.
The carbon particles may generally be joined together with adhesives to produce a more or less rigid structure. However the use of adhesives premixed with solvents or the use of adhesives that are heat activated usually results in extensive coating of the carbon particles and loss of absorption capacity, reducing the capacity of the carbon to remove contaminants.
One known method relies on the saturation of the carbon with solvents before dry adhesive is introduced to ensure that sufficient solvent is available near the surface of each carbon particle to activate the adhesive. This means that there is present, in the carbon, solvent well in excess of the amount required to activate the adhesive, and this has to be removed, generally by evaporation. In the case of water evaporation by heat, the cost of removing this excess is significant. The cost of the loss or reclamation of solvents other than water is even greater.
According to one aspect of the present invention, there is provided a method of making an aggregate comprising particles of carbon, the method comprising soaking a quantity of particulate absorbent material other than carbon with a solvent, removing any excess solvent, mixing the soaked material with a dry, solid polymeric adhesive which is soluble in the solvent, allowing the solvent to render the polymer adhesive, mixing the composition so obtained with a relatively large quantity of carbon particles, forming the mixture into a shaped body and removing any excess solvent from the body.
An advantage of the present invention is that the process does not call for saturation of the carbon. Instead, only a little more solvent than is required to activate the adhesive need be used. It has been found that certain materials will absorb solvents to a greater degree than carbon and give them up, when required to do so, more readily. If such a material is soaked with solvent and mixed with adhesive, the latter will become activated after a little time and a relatively small quantity of the mixture, on mixing with a much larger amount of carbon, can produce a firmly bonded mass.
The amount of solvent to be removed, for example by evaporation, is thereby reduced considerably. If the carbon has been washed to remove carbon dust, the presence of any residual solvent in the carbon may be ignored or it may be removed prior to mixing, by simpler and cheaper methods than those that may be used for the agglomeration.
The process is capable of producing blocks of required shape and size, of adequate strength, and having an adsorption performance substantially as good as that of loose carbon.
A wide range of different carbons may be used in the invention; a highly suitable carbon is derived from coal and has an average particle size from 5 to 10 BS mesh.
The particulate absorbent material may be wood sawdust.
A wide variety of polymeric adhesive/ solvent combinations may be used. Thus water may be used as the solvent with a soluble cellulose derivative, polyvinyl alcohol, polyacrylamide with or without formaldehyde, urea-formaldehyde resin or casein as the adhesive. Other possible solvents include ethanol, acetone, ethyl methyl ketone and carbon tetrachloride with various polymeric adhesives but water is preferred because of its low cost and absence of toxicity. A highly satisfactory combination is water as the solvent with a mixture of polyacrylamide and paraformaldehyde as adhesive.
After formation of the filter element excess solvent may be removed by various methods, including evaporation in warm air.
The duration of the drying process, and the energy required, is quite small because of the relatively small overall amount of solvent used.
In one embodiment a heat-curable adhesive is used and is cured by heat after mixing and forming the element into shape.
It is believed that in the method of the invention the particles of carbon and the absorbent material are held together by adhesion at the points of contact of the adjacent particles while the rest of the carbon particle surface is unaffected. It is generally desirable to use the minimum possible amount of adhesive both for economy and to prevent the particle surfaces being coated with adhesive, thus reducing the porosity and absorption capacity of the particles. The amount of polymer used preferably does not exceed 20% by weight of the carbon/obsorbent material composition, and is most preferably from 5 to 10% by weight.
The minimum content of absorbent material depends on the amount of solvent required and the absorption capacity of the material for the solvent.
The agglomerate of the invention may be used for making a wide variety of filter elements. In one type of filter it may be enclosed in a highly permeable textile material, which may be non-woven, to provide an air filter.
Embodiments of the invention will be described by way of illustration in the following Examples.
Example I 30 g of sawdust was soaked in cold water overnight, drained under gravity for 15 min.
and stirred while adding 15 g of hydroxypropylmethyl cellulose (Celacol Registered Trade Mark HPM 5000 DS). The mixture was allowed to stand for 1 hour and then mixed with 230 g of dry carbon having a grain size of 5-10 BS mesh (Grade 203A supplied by Suttcliffe Speakman Co. Ltd.).
The mixture was formed into a filter element and dried by heating to evaporate the water.
The element was very porous, rigidly aggregated and highly suitable for use as an air purification element.
Example 2 60 g of sawdust was soaked in cold water overnight, drained under gravity for 15 min.
and stirred while adding 180 g of Celacol HPM 5000 DS. The mixture was allowed to stand for 30 minutes and mixed with 3000g of carbon (203A) which had previously been washed and drained for 3 min. The mixture was formed into a filter element as in Example 1. A satisfactory air purification element was again obtained.
WHAT WE CLAIM IS: 1. A method of making an aggregate comprising particles of carbon which comprises soaking particles of an absorbent material other than carbon with a solvent, removing any excess solvent, mixing the soaked material with a dry, solid polymeric adhesive material which is soluble in the solvent, allowing the solvent to render the polymeric material adhesive, mixing the composition so obtained with carbon particles, forming the mixture into a shaped body and removing any residual solvent from the body.
2. A method according to claim 1, in which the absorbent material is sawdust.
3. A method according to claim 1 or 2, in which the solvent is water.
4. A method according to any preceding claim, in which the polymeric material is a cellulose derivative, polyvinyl alcohol, polyacrylamide with or without formaldehyde, a urea-formaldehyde resin or casein.
5. A method according to any preceding claim, in which the weight of dry polymeric material is not more than 20% of the weight of the carbon and absorbent material combined.
6. A method according to claim 5, in which the weight of dry polymeric material is from 5 to 10% of the weight of the carbon and absorbent material combined.
7. A method according to any preceding claim, in which the shaped body is heated.
8. A method according to any preceding claim, in which the carbon is washed to remove dust before mixing with said soaked material.
9. A method according to any preceding claim, in which the carbon has a particle
**WARNING** end of DESC field may overlap start of CLMS **.

Claims (12)

  1. **WARNING** start of CLMS field may overlap end of DESC **.
    be wood sawdust.
    A wide variety of polymeric adhesive/ solvent combinations may be used. Thus water may be used as the solvent with a soluble cellulose derivative, polyvinyl alcohol, polyacrylamide with or without formaldehyde, urea-formaldehyde resin or casein as the adhesive. Other possible solvents include ethanol, acetone, ethyl methyl ketone and carbon tetrachloride with various polymeric adhesives but water is preferred because of its low cost and absence of toxicity. A highly satisfactory combination is water as the solvent with a mixture of polyacrylamide and paraformaldehyde as adhesive.
    After formation of the filter element excess solvent may be removed by various methods, including evaporation in warm air.
    The duration of the drying process, and the energy required, is quite small because of the relatively small overall amount of solvent used.
    In one embodiment a heat-curable adhesive is used and is cured by heat after mixing and forming the element into shape.
    It is believed that in the method of the invention the particles of carbon and the absorbent material are held together by adhesion at the points of contact of the adjacent particles while the rest of the carbon particle surface is unaffected. It is generally desirable to use the minimum possible amount of adhesive both for economy and to prevent the particle surfaces being coated with adhesive, thus reducing the porosity and absorption capacity of the particles. The amount of polymer used preferably does not exceed 20% by weight of the carbon/obsorbent material composition, and is most preferably from 5 to 10% by weight.
    The minimum content of absorbent material depends on the amount of solvent required and the absorption capacity of the material for the solvent.
    The agglomerate of the invention may be used for making a wide variety of filter elements. In one type of filter it may be enclosed in a highly permeable textile material, which may be non-woven, to provide an air filter.
    Embodiments of the invention will be described by way of illustration in the following Examples.
    Example I
    30 g of sawdust was soaked in cold water overnight, drained under gravity for 15 min.
    and stirred while adding 15 g of hydroxypropylmethyl cellulose (Celacol Registered Trade Mark HPM 5000 DS). The mixture was allowed to stand for 1 hour and then mixed with 230 g of dry carbon having a grain size of 5-10 BS mesh (Grade 203A supplied by Suttcliffe Speakman Co. Ltd.).
    The mixture was formed into a filter element and dried by heating to evaporate the water.
    The element was very porous, rigidly aggregated and highly suitable for use as an air purification element.
    Example 2
    60 g of sawdust was soaked in cold water overnight, drained under gravity for 15 min.
    and stirred while adding 180 g of Celacol HPM 5000 DS. The mixture was allowed to stand for 30 minutes and mixed with 3000g of carbon (203A) which had previously been washed and drained for 3 min. The mixture was formed into a filter element as in Example 1. A satisfactory air purification element was again obtained.
    WHAT WE CLAIM IS: 1. A method of making an aggregate comprising particles of carbon which comprises soaking particles of an absorbent material other than carbon with a solvent, removing any excess solvent, mixing the soaked material with a dry, solid polymeric adhesive material which is soluble in the solvent, allowing the solvent to render the polymeric material adhesive, mixing the composition so obtained with carbon particles, forming the mixture into a shaped body and removing any residual solvent from the body.
  2. 2. A method according to claim 1, in which the absorbent material is sawdust.
  3. 3. A method according to claim 1 or 2, in which the solvent is water.
  4. 4. A method according to any preceding claim, in which the polymeric material is a cellulose derivative, polyvinyl alcohol, polyacrylamide with or without formaldehyde, a urea-formaldehyde resin or casein.
  5. 5. A method according to any preceding claim, in which the weight of dry polymeric material is not more than 20% of the weight of the carbon and absorbent material combined.
  6. 6. A method according to claim 5, in which the weight of dry polymeric material is from 5 to 10% of the weight of the carbon and absorbent material combined.
  7. 7. A method according to any preceding claim, in which the shaped body is heated.
  8. 8. A method according to any preceding claim, in which the carbon is washed to remove dust before mixing with said soaked material.
  9. 9. A method according to any preceding claim, in which the carbon has a particle
    13. A filter element, comprising an aggregate according to claims 11 or 12.
    size from 5 to 10 mesh.
  10. 10. A method of making an aggregate, substantially as hereinbefore described in the Examples.
  11. 11. An aggregate, when made by a method according to any preceding claim.
  12. 12. An aggregate according to claim 11, in which the shaped body is covered with a textile material
GB921577A 1978-01-23 1978-01-23 Carbon aggregates Expired GB1571924A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB921577A GB1571924A (en) 1978-01-23 1978-01-23 Carbon aggregates

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB921577A GB1571924A (en) 1978-01-23 1978-01-23 Carbon aggregates

Publications (1)

Publication Number Publication Date
GB1571924A true GB1571924A (en) 1980-07-23

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Family Applications (1)

Application Number Title Priority Date Filing Date
GB921577A Expired GB1571924A (en) 1978-01-23 1978-01-23 Carbon aggregates

Country Status (1)

Country Link
GB (1) GB1571924A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2475921A1 (en) * 1980-02-19 1981-08-21 Schumachersche Fabrik Gmbh Co PROCESS FOR THE PREPARATION OF FILTER BODIES FOR THE FINE FILTRATION OF FLUIDS
EP0678320A1 (en) * 1994-04-18 1995-10-25 Aisaburo Yagishita Method of fabricating molded filter element
EP1247572A1 (en) * 2001-04-03 2002-10-09 MSA Auer GmbH Process for the preparation of a filter body

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2475921A1 (en) * 1980-02-19 1981-08-21 Schumachersche Fabrik Gmbh Co PROCESS FOR THE PREPARATION OF FILTER BODIES FOR THE FINE FILTRATION OF FLUIDS
EP0678320A1 (en) * 1994-04-18 1995-10-25 Aisaburo Yagishita Method of fabricating molded filter element
US5593626A (en) * 1994-04-18 1997-01-14 Yagishita; Aisaburo Method of fabricating molded filter element
EP1247572A1 (en) * 2001-04-03 2002-10-09 MSA Auer GmbH Process for the preparation of a filter body

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Legal Events

Date Code Title Description
PS Patent sealed
732 Registration of transactions, instruments or events in the register (sect. 32/1977)
PCNP Patent ceased through non-payment of renewal fee

Effective date: 19970123